#include<iostream>

class Boat;
class Car{
    int size;
public:
    void setSize(int j){size =j;}
    int getSize()const{return size;}
    friend int leisure(int t,const Car& c,const Boat& b);
};

class Boat{
    int size;
public:
    void setSize(int j){size = j;}
    int getSize()const{return size;}
    friend int leisure(int t,const Car& c,const Boat& b);
};
int leisure(int y,const Car& c,const Boat& b){
    return t*c.size*b.size;
}
int main(){
    Car c;
    c.setSize(2);
    Boat b;
    b.setSize(3);
    std::cout<<leisure(5,c,b);
}